using System;
using System.Collections.Generic;

namespace ConsoleApp1
{
    static class MyLinq
    {
        public static IEnumerable<int> Where(this int[] arr, Func<int, bool> cond)
        {
            return new int[] { 2, 4, 6, 8 };
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8 };
            var query = from x in arr where x % 2 == 0 select x;
            foreach (int x in query) Console.Write(x + "\t");
        }
    }
}